Benthic Research Articles

Coverage estimation of benthic habitat features by semantic segmentation of underwater imagery from South-eastern Baltic reefs using deep learning models

Underwater imagery (UI) is an important and sometimes the only tool for mapping hard-bottom habitats. With the development of new camera systems, from hand-held or simple “drop-down” cameras to ROV/AUV-mounted video systems, video data collection has increased considerably. However, the processing and analysing of vast amounts of imagery can become very labour-intensive, thus making it ineffective both time-wise and financially. This task could be simplified if the processes or their intermediate steps could be done automatically. Luckily, the rise of AI applications for automatic image analysis tasks in the last decade has empowered researchers with robust and effective tools. In this study, two ways to make UI analysis more efficient were tested with eight dominant visual features of the Southeastern Baltic reefs: 1) the simplification of video processing and expert annotation efforts by skipping the video mosaicking step and reducing the number of frames analysed; 2) the application of semantic segmentation of UI using deep learning models. The results showed that the annotation of individual frames provides similar results compared to 2D mosaics; moreover, the reduction of frames by 2–3 times resulted in only minor differences from the baseline. Semantic segmentation using the PSPNet model as the deep learning architecture was extensively evaluated, applying three variants of validation. The accuracy of segmentation, as measured by the intersection-over-union, was mediocre; however, estimates of visual coverage percentages were fair: the difference between the expert annotations and model-predicted segmentation was less than 6–8%, which could be considered an encouraging result.

Herbivorous Reef Fish Interaction with the Habitat and Physicochemical Variables in Coral Ecosystems in the Mexican Tropical Pacific

Herbivorous fish can mediate spatial competition between algae and corals, which is crucial for coral ecosystems. However, in areas with limited coral coverage like the Mexican tropical Pacific (MTP), this dynamic is not fully understood. This study, using a functional trait approach and ordination analysis, explores whether herbivorous reef fish assemblage influences the benthic habitat components or if physicochemical factors define the habitat variability in the MTP’s Cleofas and Marietas insular systems. We analyzed if this relationship persisted across systems and over time, and identified species traits tied to habitat variability. Island comparison analyses between Cleofas and Marietas reveal that both herbivorous reef fish and physicochemical variables shape the habitat. Cleofas had larger mobile herbivorous fish that formed groups related mostly to macroalgae cover. In contrast, temporal analysis of Marietas shows that the habitat is primarily shaped by physicochemical variables with herbivorous fish being mainly small farmer species related to branching corals. Notably, these closely situated insular systems present varied ecosystem mediators, influenced by diverse drivers including fish traits and environmental factors. This study underscores the potential of employing a framework of ecological species traits combined with ordination methods to unravel the distinct site dynamics that contribute to the persistence of coral ecosystems within the MTP.

Benthic Habitat Classification Using Sentinel-2a Image With And Without Water Column Correction In Pengudang Village, Bintan Regency

Research on the mapping of benthic habitats in the waters of Pengudang Village, Bintan Regency, uses Sentinel-2A imagery. This mapping process has the potential to display the results of classification of benthic habitats in shallow waters. The purpose of this study was to assess the Maximum Likelihood Classification (MLH) algorithm model for mapping benthic habitat cover through Sentinel-2A satellite imagery using the lyzenga water column correction and without water column correction and to calculate the accuracy of the MLH classification results for benthic habitats in waters Pengudang Village. This classification uses a pixel-based image classification which is grouped into a cover class for each pixel. This classification groups into 4 benthic habitat classes, namely dead coral sand (KMP), sea grass (LM), live coral sand (PKH) and sand (PS). The results showed that the application of the lyzenga correction using the MLH algorithm in mapping benthic habitats resulted in a significant accuracy rate (80,00%), while the application without lyzenga correction using the MLH algorithm resulted in an accuracy rate (76,00%). These findings support the use of the lyzenga correction method which can increase the level of accuracy by (4,00%) with the MLH algorithm as a guide in better mapping of benthic habitat cover in Pengudang Village.

Mapping the distribution of sea urchin (Echinoidea) and benthic habitat using drone in the waters of Lancang Island

Sea urchins are valuable marine creatures that live in the waters of Indonesia, and typically found in seagrass and coral reefs. This study aimed to determine the distribution of sea urchins and the benthic characteristics that serve as their habitat using high resolution drone images. Object-based image analysis (OBIA) with a support vector machine algorithm is used to identify benthic habitats, while the distribution of sea urchins is determined by thresholding pixel values. A total of 812 aerial photos with a spatial resolution of 3.98 cm/px were obtained and mapped into five classes of benthic habitat (sand, rubble, seagrass, living coral, and dead coral algae). The dominant habitat class obtained was dead coral algae, with an area of 234,035 m2 (29.63%), whereas seagrass was the smallest, with an area of 74,149 m2 (9.39%). The overall accuracy of the benthic classes was 65.44%, with kappa coefficient value of 0.57. The study found that the total number of sea urchins on Lancang Island was 61,551. The dominant distribution of sea urchins was found in the living coral class with 18,094 individuals, but the highest density was in the rubble class with 1358 individuals/ha.

Characterizing anthropogenic litter pollutants in African freshwater ecosystems: A case study of Dunga Beach in Lake Victoria, Kenya

AbstractAnthropogenic litter (AL) in world's aquatic ecosystems presents critical ecological threats to environmental quality, aquatic biodiversity and human welfare. However, most studies on AL have been conducted in marine ecosystems with very little focus being given to freshwater systems like Lake Victoria. This study characterized AL pollutants in Dunga beach in Lake Victoria, Kenya, where sampling was done in the beach, riparian and benthic zones along a 100 m reach for 6 days. Across the sampled reaches, the AL associated with packaging, consumer products, building and construction, transport, electronic wastes, textile, fishery and medical materials were collected, counted, sun‐dried and weighed. AL were more abundant in the beach and riparian zone than in the benthic reaches with plastics being the dominant litter in all reaches. Based on Kruskal–Wallis rank sum test the density of AL associated with packaging and consumer products was significantly higher than other AL in all the reaches. Plastics, polystyrene and glass wastes dominated the beach zone at 31.19%, 12.14% and 11.14%, respectively. In the benthic area, the dominant wastes were plastics, fishery and polystyrene items at 22.14%, 16.34% and 12.14%, respectively. The top 10 AL pollutants in Dunga beach were as follows: bags/food wrappers, bottle caps, diapers, plastic and glass beverage bottles, plastic plates, forks, knives, spoons, straws and e‐wastes. Based on data from literature, several clear patterns emerged when comparing relative AL abundance across other aquatic habitats. In the Lake Michigan Beach, the AL were dominated by plastics (41.2%) followed by cigarettes at 29.3%. In contrast, Chicago River Beach contained more glass wastes (42.1%) while Chicago River Riparian had more plastics (57.8%). At the South Sea of Korea, fishing gear wastes were the majority AL (61.1%). AL consisting of fishing items was restricted to benthic and riparian settings, in which the benthic zone had the most items recorded. It is therefore evident that a large amount of AL waste accumulates at Dunga, Hippo point and other beaches in the world, thus justifying the need for beach cleaning and maintenance strategies. This study presents baseline data that is useful to environmental ecologists, aquatic scientists and management authorities to formulate policies, evaluate guidelines and recommend beach management strategies to conserve aquatic biodiversity, human health and aesthetic value of the freshwater habitats.

Marketing strategy of flying fish (Cypselurus sp) in Kiliga Village, East Part of Seram District

The sustainable potential of the fisheries sector in East Seram Regency includes surface fish (pelagic) and bottom fish (demersal) estimated at 128,692.2 tons/year, of which up to 2005 only 9,340.6 tons (7.79%) could be managed with a production value of 13,561,250,000. Additionally, there are several marine resources with high economic value, including sea cucumbers, lola, squid, sea turtles, and Penaide shrimp. This research will be carried out in Kiliga Village, Kiandarat District, East Seram Regency. The data used in this research includes primary and secondary data. Primary data was obtained from respondents through interviews using questionnaires, while secondary data used statistical data from the Central Statistics Agency, East Seram Regency Maritime and Fisheries Service, and other supporting data. Research data was obtained using observation, interviews, and literature study methods, as well as documentation. The results showed that the total IFAS score is 6.91, where one of the strategies needed here is that the government needs to provide outreach and training on flying fish catching and marketing training through online media as well as the existence of flying fish fishermen's cooperatives, and the total EFAS score reaches 7.48. Maintaining the quality of flying fish caught for sale will contribute to customer satisfaction, giving fishermen a chance to compete with increasingly tough competitors. The QSPM matrix results are obtained from the SWOT matrix which produces 6 alternative strategies.

Habitat-based variation in the trophic ecology of the world’s highest-altitude self-sustaining population of invasive rainbow trout

Rainbow trout (Oncorhynchus mykiss) have been widely introduced outside of their natural range and are one of the World’s most invasive species. Illegally introduced into the isolated, high-altitude (4520 m) Chungará catchment of northern Chile, rainbow trout have now been present in the system for ∼30 years and to our knowledge are the World’s highest known self-sustaining population. However, nothing is known about the status and impacts of these trout in the system. We analysed stomach contents and stable isotopes (δ13C, δ15N, δ34S) from liver and muscle to study the trophic ecology of rainbow trout from lake, river mouth and riverine habitats in the Chungará catchment to understand their basic ecology and to characterise their potential trophic interactions with native taxa. Both stomach contents and stable isotope values showed spatial differences in diet and habitat use, but also revealed that diet varied temporally within habitats. The trophic position of rainbow trout was similar in the three habitats examined and was constant over time, apart from the riverine population. Predation by rainbow trout had different potential effects across pelagic, benthic, and riverine habitats in the Chungará catchment, through the consumption of zooplankton, native amphipods, aquatic insects, and the endemic cypriniodontid fish Orestias chungarensis.

Effects of sediment disturbance by the heart urchin <i>Echinocardium cordatum</i> on the sediment–seawater solute exchange: An exclusion experiment

<p>Spatangoid heart urchins are dominant bioturbators in marine soft-sediment ecosystems worldwide. Their repeated sediment reworking prevents biogeochemical sediment stratification and colonization by other species, with implications for sedimentary reaction processes that affect the local sediment–seawater solute exchange. Here, we used a simple exclusion experiment to investigate how a subtidal <italic>Echinocardium cordatum</italic> population (18.2 ± 6.7 individuals m<sup>−2</sup>), foraging at an individual speed of ~45 cm per day affects the sediment–seawater solute exchange. To do so, we removed all heart urchins from eight one-meter-diameter areas of the 10-m deep seafloor of Man O'War Bay, Hauraki Gulf, New Zealand, and prevented recolonization and thus sediment reworking for 56 days. Subsequently, we measured the sediment–seawater exchange of O<sub>2</sub>, NO<sub>3</sub><sup>–</sup>, NO<sub>2</sub><sup>–</sup>, NH<sub>4</sub><sup>+</sup>, and N<sub>2</sub> both within and outside the exclusion areas, under light or dark conditions, and found no difference. The absence of a legacy effect of foraging <italic>E. cordatum</italic> after their removal suggests that, at least in this habitat, their influence on the sediment–seawater solute exchange may be limited to sediment being displaced in the immediate surrounding of the urchin. This unexpected result underlines the importance of evaluating the influence of bioturbators on the sediment–seawater solute exchange in the context of local environmental conditions, animal behavior, and population characteristics.</p>

Spatial distribution of benthic habitat derived from Planetscope image in shallow water of Kahyapu Village, Enggano Island

Spatial distribution of benthic habitat derived from Planetscope image in shallow water of Kahyapu Village, Enggano Island

Salinity and resource availability as drivers of Baltic benthic fungal diversity

AbstractMarine biodiversity consists of a complex network of organisms responsible for keeping the ecosystem's balance. Fungi are an understudied group of organisms despite their recognized importance for ecosystem processes and diversity. How fungi respond to environmental change remains poorly understood, especially in marine benthic habitats. The Baltic Sea is a brackish coastal ecosystem with steep environmental gradients in a relatively limited geographical area and is therefore a particularly good system to investigate the impact of different abiotic factors on benthic fungal diversity. This study used environmental DNA (eDNA) metabarcoding to analyze the spatial dynamics of benthic fungal diversity in the Baltic Sea and quantify the environmental drivers that shape these dynamics. Based on 59 stations spreading over 1145 km the results showed that benthic fungal communities were dominated by the phylum Chytridiomycota, and the fungal species Alphamyces chaetifer and Operculomyces laminatus from this phylum were the main drivers of the community structure dissimilarities observed between regions. Water depth and salinity were the main predictors of the benthic fungal community composition. The impact of nutrient availability was also significant, possibly related to the known role of Chytridiomycota species such as A. chaetifer and O. laminatus in nutrient cycling. Our results indicate that the benthic fungal diversity of the Baltic Sea is shaped by salinity gradients and nutrient availability and highlights that the current fungal biodiversity is at risk of species shift or decline with predicted changes in salinity due to climate change and intensified eutrophication.

Functional changes across marine habitats due to ocean acidification.

Global environmental change drives diversity loss and shifts in community structure. A key challenge is to better understand the impacts on ecosystem function and to connect species and trait diversity of assemblages with ecosystem properties that are in turn linked to ecosystem functioning. Here we quantify shifts in species composition and trait diversity associated with ocean acidification (OA) by using field measurements at marine CO2 vent systems spanning four reef habitats across different depths in a temperate coastal ecosystem. We find that both species and trait diversity decreased, and that ecosystem properties (understood as the interplay between species, traits, and ecosystem function) shifted with acidification. Furthermore, shifts in trait categories such as autotrophs, filter feeders, herbivores, and habitat-forming species were habitat-specific, indicating that OA may produce divergent responses across habitats and depths. Combined, these findings reveal the importance of connecting species and trait diversity of marine benthic habitats with key ecosystem properties to anticipate the impacts of global environmental change. Our results also generate new insights on the predicted general and habitat-specific ecological consequences of OA.

Recruitment of Juvenile Snapper (Lutjanidae) in the Middle Florida Keys: Temporal Trends and Fine-Scale Habitat Associations

Juvenile recruitment is a major factor in the establishment and maintenance of local population structures of coral reef fishes. An understanding of the factors that affect juvenile recruitment and survival help explain spatial and temporal patterns in adult abundance, especially of commercially and recreationally fished species. Here, we examined the distribution and juvenile recruitment of 5 snapper species: Mutton Snapper (Lutjanus analis), Lane Snapper (L. synagris), Schoolmaster (L. apodus), Gray Snapper (L. griseus), and Yellowtail Snapper (Ocyurus chrysurus) collected in 1,314 seine samples conducted between 2007 and 2019 in the Middle Florida Keys. We use a generalized linear modeling routine to assess juvenile recruitment of each species as a function of temporal, environmental, and benthic habitat variables. Interannual variability in juvenile recruitment ranged between 2 and 15—fold differences in mean predicted abundance between the highest and lowest producing years by species. Predicted recruitment varied dramatically by species in 2010 following a historic cold spell in south Florida. Three of the 5 species (Lane Snapper, Yellowtail Snapper, and Schoolmaster) exhibited the lowest observed yearly recruitment in that year, while Gray Snapper recruitment peaked. For all species, recruitment indices exhibited strong seasonal trends with peak abundances observed in the fall. Aquatic vegetation type, aquatic vegetation cover, distance from shore, and water temperature were the most important predictors of abundance. Results of this study highlight species—specific preferences for settlement habitat, demonstrate the importance of local—scale recruitment processes, and provide updated, management—relevant juvenile abundance indices for shallow water snapper in the Middle Florida Keys.

New Early Rupelian Endemic Porcellaneous Larger Foraminifera from the Prebetic Range, Westernmost Tethys. Discussion on Praerhapydionina

Abstract Peneroplis peramplus n. sp. and Spirolinella emmae n. gen., n. sp. are described from the early Rupelian of the Ibi section in the Prebetic Range (southeastern Iberia). The former is a Peneroplis species of evolute annular growth with a large bilocular megalospheric embryo. Spirolinella n. gen. is similar to Spirolina, from which it differs by a complex aperture. Spirolinella is also similar to Praerhapydionina, but it completely lacks radial partitions. It also differs in the wall texture, homogeneous in Spirolinella and with a pseudokeriotheca-like texture in Praerhapydionina. This newly observed character in Praerhapydionina will help to identify the genus and verify its presumed cosmopolitan distribution. The two new species show the same stratigraphical range, corresponding to the Shallow Benthic Zone SBZ 21, early Rupelian, and are considered endemic to the carbonate platform that developed during the Paleogene in the southeastern margin of the Iberian plate, at the westernmost Tethys.

Three-dimensional printing can provide opportunities to promote coral recruitment on disturbed reefs

Tropical corals are undergoing population declines due to disturbances. The implications of these trends are modulated by the ability of corals to support population recovery through recruitment. Current research underscores the importance of physical features of benthic surfaces in promoting coral recruitment, which creates opportunities to enhance recruitment by engineering surfaces to replicate these features with the goal of enhancing coral settlement. This study examined the interaction between the settlement of coral larvae and three-dimensional (3D) surfaces and employed 3D printing to enhance recruitment. We tested the effects of the features of microhabitats on the settlement preference, gregariousness, and survival of the brooding coral Pocillopora acuta. Grooved microhabitats that are common in the shallow (<7 m depth) backreef of Moorea, French Polynesia, were printed onto plastic tiles, and were favored for settlement by freshly released larvae from P. acuta. The percent survivorship over 20 days of coral recruits that settled in grooved microhabitats was 16.4% versus none on open flat surface. These results underscore the importance of naturally forming benthic features in promoting coral recruitment, and they highlight the potential for duplication of these features through 3D printing to enhance coral recruitment and accelerate reef restoration following damage.

Epilithic Diatom Assemblages and Indicators for the Assessment of Water Quality of Munzur Stream, Turkey

The epilithic diatoms of Munzur Stream, together with the chemistry and physical variables of the water, were examined in the samples taken annually from 3 stations on the creek between October 2016 and September 2017. A total of 69 diatom taxa were identified benthic habitat. Cocconeis placentula, Cymbella affinis, Cymbella excisiformis , Didymosphenia geminata, Gomphonema olivaceum, and Hannaea arcus became diatoms at all that reached significant relative abundance. Shannon-diversity (H’), species evenness (J’), species richness (S) in each station varied between stations and months. Regarding diversity (H), values ranged from 1.54 (in December, at S3) to 2.99 (in October, at S3). Evenness ranged from 0.09 to 0.22 at station S3 in September (at S1, in September). Evenness ranged from 0.09 at site S3 in September, to 0.22 at S1, in September. All stations and species were close to 1 value. Canonical correspondence analysis indicated that three environmental variables (TN,TP, PO4-3) significantly affected the distribution of epilithic diatom. The studied part of stream was characterized by the species susceptible to nutrients such as Didymosphenia geminata, Cymbella excisiformis and Hannaea arcus which are found in the regions located in high lands having advanced ecological status. The results of the present study highlighted the importance of diatoms as a bio-indicator for health condition of a stream.

Trophic characteristics of pelagic and bottom nekton in certain water masses in the western Chukchi Sea, by δ15N and δ13C data

To compare the trophic characteristics of pelagic- and bottom-dwelling fish in the western Chukchi Sea, isotopic composition of carbon and nitrogen (δ13С and δ15N) is considered separately for the Subarctic water mass (invaded from the Bering Sea) and local Arctic water mass. In summer of 2018 and 2019, the proper water mass occupied mostly the area southward from 71оN and the latter one – northward from this latitude. The isotopic composition of both pelagic and bottom nekton in the southern area was characterized by higher values of δ13C (up to 2 % higher) and low values of δ15N (up to 1 % lower) in comparison with those in the northern area. That was interpreted that in the southern area, within the water from the Bering Sea, more than 90 % of the sampled bottom fish species were linked with prey from the bottom community. In the northern area, within the Arctic water, all samples of bottom fish were characterized by minimal content of heavy carbon δ13C isotope, comparable with the values in samples of pelagic fish that indicated a significant role of pelagic prey in nutrition of the bottom nekton.

Molecular responses of sponge larvae exposed to partially weathered condensate oil

Anthropogenic inputs of petroleum hydrocarbons into the marine environment can have long lasting impacts on benthic communities. Sponges form an abundant and diverse component of benthic habitats, contributing a variety of important functional roles; however, their responses to petroleum hydrocarbons are largely unknown. This study combined a traditional ecotoxicological experimental design and endpoint with global gene expression profiling and microbial indicator species analysis to examine the effects of a water accommodated fraction (WAF) of condensate oil on a common Indo-Pacific sponge, Phyllospongia foliascens. A no significant effect concentration (N(S)EC) of 2.1 % WAF was obtained for larval settlement, while gene-specific (N(S)EC) thresholds ranged from 3.4 % to 8.8 % WAF. Significant shifts in global gene expression were identified at WAF treatments ≥20 %, with larvae exposed to 100 % WAF most responsive. Results from this study provide an example on the incorporation of non-conventional molecular and microbiological responses into ecotoxicological studies on petroleum hydrocarbons.

Trawling-induced change in benthic effect trait composition – A multiple case study

IntroductionThe importance of the response-effect trait dichotomy in marine benthic ecology has garnered recent attention. Response traits, characterising species responses to environmental variations, have been a dominant focus in the development of ecological indicators for ecosystem health assessment. In contrast, effect traits, expressing effects of organism activities on the ecosystem, still do not benefit from an equal interest in spite of the complementary facet that they provide to complete our understanding of functional diversity and ecosystem vulnerability. In this study, we explore the consequences of disturbance by bottom trawl fisheries on benthic effect trait composition.MethodsTo this end, we used different contexts of environmental and trawling conditions from thirteen case studies in European waters and apply the same analytical procedure to derive a gradient that solely account for trawling-induced disturbance (Partial RLQ analysis).ResultsBottom trawling was found to be a selective force of benthic effect trait composition in a majority of case studies. In general, tube-dwelling species were more typical of low trawling frequencies, whereas deep burrowing species were more resistant at high trawling frequencies. Although we report significantly deleterious effects of trawling on benthic ecosystem functions, the effect trait pattern along the gradient was never related to life span, a key response trait generally assumed to express recoverability following disturbance. Furthermore, we show that trends in species multi-functionality and community functional diversity can be negative or positive along the trawling intensity gradient.DiscussionWe discuss the relevance of these results in light of recent developments in the framework of response and effect trait dichotomy, and provide guidelines of trait data analysis in the context of trawl fisheries impact on the sea floor. Our findings emphasize the importance of fundamental concepts from functional ecology in this context and represent a first step toward an assessment of trawling effect more oriented on benthos-mediated biogeochemical processes.

Low-Tech and Low-Cost System for High-Resolution Underwater RTK Photogrammetry in Coastal Shallow Waters

Monitoring coastal seabed in very shallow waters (0–5 m) is a challenging methodological issue, even though such data is of major importance to many scientific and technical communities. Over the years, Structure-from-Motion (SfM) photogrammetry has emerged as a flexible and inexpensive method able to provide both a 3D model and high-resolution imagery of the seabed (~cm level). In this study, we propose a low-cost (about USD 1500), adaptable, lightweight and easily dismantled system called POSEIDON (for Platform Operating in Shallow-water Environment for Imaging and 3D reconstructiON). This prototype combines a floating support (typically a bodyboard), two imagery sensors (here, GoPro® cameras) and an accurate positioning system using Real Time Kinematic GNSS. Validation of this method was deployed in a macrotidal zone, comparing on the foreshore the point cloud provided by POSEIDON “SfM bathymetry” and by classical terrestrial SfM survey. Mean deviation was 5.2 cm and standard deviation was 4.6 cm. Such high-resolution SfM bathymetric surveys have a great potential for a wide range of applications: micro-bathymetry, hydrodynamics (bottom roughness), benthic habitats, ecological inventories, archaeology, etc.

The Western Channel Observatory: a century of physical, chemical and biological data compiled from pelagic and benthic habitats in the western English Channel

Abstract. The Western Channel Observatory (WCO) comprises a series of pelagic, benthic and atmospheric sampling sites within 40 km of Plymouth, UK, that have been sampled by the Plymouth institutes on a regular basis since 1903. This longevity of recording and the high frequency of observations provide a unique combination of data; for example temperature data were first collected in 1903, and the reference station L4, where nearly 400 planktonic taxa have been enumerated, has been sampled on a weekly basis since 1988. While the component datasets have been archived, here we provide the first summary database bringing together a wide suite of the observations. This provides monthly average values of some of the key pelagic and benthic measurements for the inshore site L4 (50∘15.00′ N, 4∘13.02′ W; approx. depth 55 m), the offshore site E1 (50∘02.00′ N, 4∘22.00′ W; approx. depth 75 m) and the intermediate L5 site (50∘10.80′ N, 4∘18.00′ W; approx. depth 58 m). In brief, these data include the following: water temperature (from 1903); macronutrients (from 1934); dissolved inorganic carbon and total alkalinity (from 2008); methane and nitrous oxide (from 2011); chlorophyll a (from 1992); high-performance liquid chromatography (HPLC)-derived pigments (from 1999); <20 µm plankton by flow cytometry, including bacteria (8 functional groups from 2007); phytoplankton by microscopy (6 functional groups from 1992); microplankton and mesozooplankton from FlowCam (6 groups from 2012); Noctiluca sp. dinoflagellate (from 1997); mesozooplankton by microscopy (8 groups from 1988); Calanus helgolandicus egg production rates (from 1992); fish larvae from the Young Fish Trawl survey (4 groups from 1924); benthic macrofauna (4 groups from 2008); demersal fish (19 families from 2008); blue shark, Prionace glauca (from 1958); and 16S alpha diversity for sediment and water column (from 2012). These data have varying coverage with respect to time and depth resolution. The metadata tables describe each dataset and provide pointers to the source data and other related Western Channel Observatory datasets and outputs not compiled here. We provide summaries of the main trends in seasonality and some major climate-related shifts that have been revealed over the last century. The data are available from the Data Archive for Seabed Species and Habitats (DASSH): https://doi.org/10.17031/645110fb81749 (McEvoy and Atkinson, 2023). Making these data fully accessible and including units of both abundance and biomass will stimulate a variety of uptakes. These may include uses as an educational resource for projects, for models and budgets, for the analysis of seasonality and long-term change in a coupled benthic–pelagic system, or for supporting UK and north-eastern Atlantic policy and management.